textproduct: Rapid City

KEY MESSAGES

- A cold frontal passage with light snow will pass through northwest SD for tonight through Saturday

- Cooler temperatures for the weekend, warming up next week

- Slight chance for precipitation early next week

DISCUSSION

(This Evening Through Friday) Issued at 1238 PM MST Fri Feb 27 2026

Current upper-air water vapor analysis depicts split-flow over western/central CONUS. Ridging is positioned over the West Coast stretching from OR down to Baja California, the northern flow broad trough is positioned over eastern Canada stretching from the Hudson Bay down to the Great Lakes with a smaller southern flow trough stretching from IL/IN down to MS, and a shortwave aloft with a surface-low positioned over western Ontario with a cold front extending from the low through northern MN and into ND. WV indicates increasing high/mid-layer cloud cover moving into northwest SD as the cold front approaches from ND. Surface observations show continued near-critical to critical fire weather conditions for much of the forecast region. RH values across parts of northeast WY, southwestern SD, and south-central SD remain around or below 20 percent with northwest wind gusts up to 34 mph. Temperatures across the region are currently in the upper 40s over northwest SD to upper 50s to low 60s for northeast WY and the rest of western SD. Due to the ongoing near-critical to critical fire weather conditions, a Red Flag Warning is in effect for portions of northeast WY and southwest/south-central SD until 01Z.

Tonight into Saturday, the northern flow (northwest orientation) will slide southeast over western ND and into central/eastern SD, clipping northwest SD. The jet streak embedded in the flow will dictate where the snow band will set up as it moves through the region with current model trends keeping the band north and east of our forecast region. Snow should begin to move into the region this evening and last through mid Saturday morning. Current model runs for snowfall totals show a range from a trace to 2 inches for far northwest SD (~60 to 25 percent chance, respectively, via NBM-CONUS). The cold front in ND will begin to move into the region tonight into Saturday before fully overtaking the forecast region Saturday evening, resulting in a wide range of high temperatures for Saturday (from 30s over northwest SD to low 50s for southwest SD). Northerly winds will pick up as the front moves through with gusts reaching 35 mph.

Sunday, the jet streak and colder air will shift to the south and east as the ridge over the West Coast moves east, resulting in a similar high temperature pattern as Saturday. A surface-low, positioned off the northern CA coast, will begin to move onshore Sunday night into Monday morning, brining our next chance for precipitation Monday into Tuesday. Chances for impactful precipitation during this system look to be minimal. Thursday/Friday will be the next system of interest, brining another chance for much needed precipitation.

AVIATION

(For the 18Z TAFS Through 18Z Saturday) Issued At 1025 AM MST Fri Feb 27 2026

VFR conditions are expected through the period. Gusty northwest winds will increase across western South Dakota through the early afternoon with gusts of up to 35 kt expected across northwestern South Dakota. Winds will subside around sunset, before increasing again late Saturday morning. North northwest winds with gusts of 30kts to 35kts will be common by midday Saturday.

FIRE WEATHER

Issued At 1238 PM MST Fri Feb 27 2026

Very dry air will persist across portions of northeastern Wyoming and southwestern into south-central South Dakota this afternoon. Minimum relative humidities will drop to 15-20 percent as northwest winds increase to 10-25 mph with gusts from 25-40 mph. The strongest winds will be across the western South Dakota plains. MinRH <=15 percent and frequent wind gusts >=25mph this afternoon combined with D1 to D2 drought conditions will exacerbate the fire potential. The combination of low humidity values and gusty winds will create critical fire weather conditions this afternoon.

Elevated fire weather conditions will cover the rest of northeastern Wyoming and northwestern South Dakota this afternoon as a cold front moves in this evening. The front will bring cooler temperatures Saturday/Sunday. Precipitation will be limited to locations near the North Dakota/South Dakota border, where light snow accumulation is expected.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 6 PM MST /7 PM CST/ this evening for SDZ322-326-333>335. WY...Red Flag Warning until 6 PM MST this evening for WYZ315-317.